<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var year = Number(prompt('请输入年份'));
            if(year%4==0 && year%100!=0 || year%400==0){
                alert("闰年");
            }else{
                alert('平年');
            }   
    </script>
</body>
</html>